Physics – Introduction to Momentum

In calculus, the moments of a system are discrete measurable quantities associated with the geometrical structure of the system. The first moments of a system are the centre of mass, which is often the case for a closed system, such as a harmonic constant. The second moments are the rotational momentum and can be either zero or infinite depending on the structure of the system. In general terms, the first moments refers to the condition of equilibrium, while the second term captures the idea that after the initial input the system is able to ‘unchange’ to some other state. It is in situations like these that moments become important in determining the solutions to a system’s equations.


Momentum, as defined above, is the difference between the initial value of a body and its final position after the force that produced it has been converted into a different form. Thus, a body at rest may have no moment due to the simple Law of Gravity, but jump start if we apply some kind of external force. Thus, for instance, when a baseball is struck by a bat, there is some kind of momentum that is created when the bat hits the ball, which is then converted into an energy change due to the movement of the baseball down the path of impact. A force then pulls the ball back toward the pitcher’s glove where it is hit by another player.

Momentum plays an important role in the operation of magnets. In the magnets’ case, the moment created by the turning effect is that the poles repel each other, which creates a force field. When the poles repulse each other, this creates a net force, which is a force that pushes on a surface, such as a magnet, while it helps repel it. Thus, a magnet with a north pole attracts iron ions, which have a positive charge, while a magnet with a south pole attracts magnetizing compounds, which have a negative charge.

The law of conservation of moments shows that the only way to calculate the momentum of a system is by calculating the time-reversal of its angular momentum. Thus, any system with a beginning momentum, such as a spring, has an end momentum, such as the torque that it exercises, due to its moment. The only way to calculate the time-reversal is to integrate the moment of reversal with the time for the maximum force on the system. In the case of a spring, this would be the instantaneous force of its pole, the turning of its inner ring, and its diagonal position. The time for the maximum of this force, its moment of integration, is the time it takes for the spring to go to rest after one complete revolution.

If you integrate your moment with the time for the maximum angular momentum to reach its critical point, you get the time for the rotation of your frame to reach its reference point. This is very useful in the case of rotating magnets; since the moment of integration depends only on the orientation of a magnet’s axis to its reference point, it is easy to calculate. The torque or force that a magnet exerts on a wire will always be in a single direction when the magnet is spinning about its axis of rotation. The moment of integration, however, can be linearly improved by altering the orientation of the axis of rotation of a magnet.

Momentum is actually a force that accumulates over time, without changing its direction of rotation with time. The moment of inertia, which is the product of all this accumulated force, is basically the product of all the forces acting on an object at the same time. Momentum then becomes a force, which exerts itself against any motion in the object, due to its orientation. Thus, in Physics, a moment can be defined as the sum of all the force that acts on an object, for some fixed time interval. The sum is known as the moment of inertia, which directly relates to the acceleration of an object, as stated before.